I use "Seal a Block Concrete Degreaser " there is also a product for tarmac, It costs about £40. I've had quite good results from this product but it all depends on how old the oil stain is or whether or not it is oil stain on oil stain. You apply the product to dry pavers, agitate with a stiff broom, leave for 15mins and rinse thoroughly with pressure washer, for stubborn stains repeat as necessary.
I'm not convinced one can offer a complete stain removal service to customers and it would be foolhardy to boast one. Customers rarely mention they have oil stains on their driveways so I'm cautious when visiting a customer to generate a quotation for driveway cleaning.
I've discovered the most sensible approach to an oil stain removal requests by potential customers is to ask for temporary removal of any vehicles on the driveway to look for oil stains beneath their parked cars and also to ascertain the condition of the drive beneath the vehicle. Any reluctance to this request then beware as after cleaning they may blame you for any anomaly they find. Take photographs of any damage or stains on the pavers for future reference. Mention to the customer that you can only offer a oil stain reduction service and some shading may still remain after cleaning. You must state this very clearly on the quotation about any oil stain or damage on the driveway, its not your fault the customer or previous tenants has let the driveway get into a bad state.
